This invention relates to thermal tools and tips for such tools and more specifically to a novel and useful tool and tip for performing operations such as soldering on micro-size electronic components.
It is a primary object of this invention to provide a thermal tool having a directly heated tip capable of performing soldering, thermal parting and other operations where, for example, a precise amount of heat is required to be applied to the very narrow (3-5 mil) connecting leads and associated circuitry of small electronic components without the substantail risk of destroying the leads, the component itself and possibly adjacent leads and components. Further, because the aforementioned leads are extremely thin in addition to their narrow width, they are particularly susceptible to being severed if the pressure of the working end of the tip against the lead is too great of damaged beyond use of an unsatisfactory configuration of the working surface of the tip itself.
The prior art structure in this area of which applicants are aware is exemplified, for example, ion U.S. Pat. No. 3,558,854 which discloses a thermal tool having a directly heated tip for applying heat to relatively small areas with some degree of control over the initial contact pressure exerted by the tip on the object to be heated. The degree of initial contact pressure is controlled by the use of compression springs located in the handle or grip member of the tool itself adjacent the ends of the tip rendering the tip capable of in and out motion only. In addition, the tip itself is made of a relatively heavy gauge material which precludes its successful use for applying heat to the very narrow leads of electronic components whose widths measure between 3 and 5 thousandths of an inch. To vary the amount of pressure exerted by the tip of the device of the prior art, it would appear to be necessary to both change the springs as well as take into consideration the flexibility of the power cord leads indirectly connected thereto--a very difficult, time-consuming and impractical procedure. The use of a loop of very thin wire has the disadvantage that the wire is inherently flexible and too easily misshaped during handling and use.
The present invention overcomes the aforementioned disadvantages of the prior art by providing a tip which is small enough for soldering or thermal parting operations and the like on the leads of micro-miniature components, has sufficient rigidity to prevent its being misshaped during handling and use but which has the desired degree of flexibility between the working end of the tip and the grip member to which it is attached to thereby reduce to a minimum the possibility of damage to the component when the tip comes in contact therewith. This is accomplished by fashioning the tip out of very small diameter, heat generating-type wire which is shaped in the form of a loop attached at its ends to legs adapted to be inserted into the end of a grip member of the type disclosed in U.S. Pat. No. 3,526,750. The working end of the tip, i.e. the area of the loop adjacent its midpoint, can be further shaped as desired depending on the application. To then impart the desired degree of flexibility between the working tip and the legs or the grip member, the loop of wire is twisted a certain degree with respect to a common plane through the legs at a point intermediate the working tip and the legs such that a plane through the intermediate portion is at an angle relative to the common plane. If the location of the twist is closer to the legs, the working end of the tip will have greater rigidity with respect to the legs and grip member and more flexibility if twisted closer to the working end of the tip. The tip of the present invention thus has springing action in all directions and not only in and out as seen in the above referenced prior art thermal tool.
It is therefore a further pirmary object of the present invention to provide a superior, directly-heated tip for thermal tools.
It is another object of the present invention to provide a tip which, due to its unique construction, is particularly suitable for soldering, thermal parting and stripping the insulation from wires and the like associated wiht micro-miniature electronic components.
It is yet another object of the present invention to provide tip for a thermal tool having a continuous, smooth working surface of any desired configuration with no sharp edges to dig or cut delicate workpieces.
It is a further object of the present invention to provide a tip for a thermal tool whose working portion can be made to possess various degrees of flexibility with respect to the member holding the tip to thereby prevent damage to the workpiece resulting from the application ofexcessive initial pressure thereon.
It is a still further object of the present invention to provide a tip for a thermal tool which is simple in construction, inexpensive to make and easily and efficiently used in conjunction with conventinoal grip members already available in the marketplace.